GLAPI/glPolygonMode: Difference between revisions
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== Function Definition == | == Function Definition == | ||
void '''glPolygonMode'''(GLenum | void '''glPolygonMode'''(GLenum {{param|face}}, GLenum {{param|mode}}); | ||
; face | ; face | ||
: Specifies the polygons that | : Specifies the polygons that {{param|mode}} applies to. Must be {{enum|GL_FRONT_AND_BACK}} for front- and back-facing polygons. | ||
; mode | ; mode | ||
: Specifies how polygons will be rasterized. Accepted values are {{ | : Specifies how polygons will be rasterized. Accepted values are {{enum|GL_POINT}}, {{enum|GL_LINE}}, and {{enum|GL_FILL}}. The initial value is {{enum|GL_FILL}} for both front- and back-facing polygons. | ||
== Description == | == Description == | ||
'''glPolygonMode''' controls the interpretation of polygons for rasterization. | '''glPolygonMode''' controls the interpretation of polygons for rasterization. {{param|face}} describes which polygons {{param|mode}} applies to: both front and back-facing polygons ({{enum|GL_FRONT_AND_BACK}}). The polygon mode affects only the final rasterization of polygons. In particular, a polygon's vertices are lit and the polygon is clipped and possibly culled before these modes are applied. | ||
Three modes are defined and can be specified in | Three modes are defined and can be specified in {{param|mode}}: | ||
; {{ | ; {{enum|GL_POINT}} | ||
: Polygon vertices that are marked as the start of a boundary edge are drawn as points. Point attributes such as {{ | : Polygon vertices that are marked as the start of a boundary edge are drawn as points. Point attributes such as {{enum|GL_POINT_SIZE}} and {{enum|GL_POINT_SMOOTH}} control the rasterization of the points. Polygon rasterization attributes other than {{enum|GL_POLYGON_MODE}} have no effect. | ||
; {{ | ; {{enum|GL_LINE}} | ||
: Boundary edges of the polygon are drawn as line segments. Line attributes such as {{ | : Boundary edges of the polygon are drawn as line segments. Line attributes such as {{enum|GL_LINE_WIDTH}} and {{enum|GL_LINE_SMOOTH}} control the rasterization of the lines. Polygon rasterization attributes other than {{enum|GL_POLYGON_MODE}} have no effect. | ||
; {{ | ; {{enum|GL_FILL}} | ||
: The interior of the polygon is filled. Polygon attributes such as {{ | : The interior of the polygon is filled. Polygon attributes such as {{enum|GL_POLYGON_SMOOTH}} control the rasterization of the polygon. | ||
== Examples == | == Examples == | ||
| Line 43: | Line 43: | ||
== Errors == | == Errors == | ||
{{ | {{enum|GL_INVALID_ENUM}} is generated if either {{param|face}} or {{param|mode}} is not an accepted value. | ||
== Associated Gets == | == Associated Gets == | ||
{{apifunc|glGet}} with argument {{enum|GL_POLYGON_MODE}} | |||
== See Also == | == See Also == | ||
{{apifunc|glLineWidth}}, {{apifunc|glPointSize}} | |||
== Copyright == | == Copyright == | ||
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [ | Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [https://khronos.org/registry/OpenGL-Refpages/LICENSES/LicenseRef-FreeB.txt LicenseRef-FreeB]. | ||
[[Category:Core API Ref Rasterization|PolygonMode]] | [[Category:Core API Ref Rasterization|PolygonMode]] | ||
[[Category:Core API Reference|PolygonMode]] | [[Category:Core API Reference|PolygonMode]] | ||
Latest revision as of 22:08, 5 February 2021
| Core in version | 4.6 | |
|---|---|---|
| Core since version | 1.0 | |
glPolygonMode: select a polygon rasterization mode
Function Definition
void glPolygonMode(GLenum face, GLenum mode);
- face
- Specifies the polygons that mode applies to. Must be GL_FRONT_AND_BACK for front- and back-facing polygons.
- mode
- Specifies how polygons will be rasterized. Accepted values are GL_POINT, GL_LINE, and GL_FILL. The initial value is GL_FILL for both front- and back-facing polygons.
Description
glPolygonMode controls the interpretation of polygons for rasterization. face describes which polygons mode applies to: both front and back-facing polygons (GL_FRONT_AND_BACK). The polygon mode affects only the final rasterization of polygons. In particular, a polygon's vertices are lit and the polygon is clipped and possibly culled before these modes are applied.
Three modes are defined and can be specified in mode:
- GL_POINT
- Polygon vertices that are marked as the start of a boundary edge are drawn as points. Point attributes such as GL_POINT_SIZE and GL_POINT_SMOOTH control the rasterization of the points. Polygon rasterization attributes other than GL_POLYGON_MODE have no effect.
- GL_LINE
- Boundary edges of the polygon are drawn as line segments. Line attributes such as GL_LINE_WIDTH and GL_LINE_SMOOTH control the rasterization of the lines. Polygon rasterization attributes other than GL_POLYGON_MODE have no effect.
- GL_FILL
- The interior of the polygon is filled. Polygon attributes such as GL_POLYGON_SMOOTH control the rasterization of the polygon.
Examples
To draw a surface with outlined polygons, call
glPolygonMode(, );
Notes
Vertices are marked as boundary or nonboundary with an edge flag. Edge flags are generated internally by the GL when it decomposes triangle stips and fans.
Errors
GL_INVALID_ENUM is generated if either face or mode is not an accepted value.
Associated Gets
glGet with argument GL_POLYGON_MODE
See Also
Copyright
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see LicenseRef-FreeB.